Yes, I use a 5 stage RODI and I did a 20% water change 12 days ago but nitrates shouldn't be that high. I have a 44 gallon with 2 turbos, over 10 tonga snails, and a couple of porcelain crabs. As for fish, I have 4 clowns, 1 yellow tail damsel, and 1 firefish. I feed my fish frozen food once per...